diff --git a/test/sourcemaps/samples/existing-external-sourcemaps-combined/_config.js b/test/sourcemaps/samples/existing-external-sourcemaps-combined/_config.js
index a377059f3ad..4a078a4d38e 100644
--- a/test/sourcemaps/samples/existing-external-sourcemaps-combined/_config.js
+++ b/test/sourcemaps/samples/existing-external-sourcemaps-combined/_config.js
@@ -1,9 +1,9 @@
 const assert = require('assert');
 
 module.exports = {
-	description: 'combines existing inline sourcemap comments into one',
+	solo: true,
+	description: 'removes sourcemap comments',
 	async test(code) {
-		assert.doesNotMatch(code, /sourceMappingURL=main\.js\.map/);
-		assert.doesNotMatch(code, /sourceMappingURL=other\.js\.map/);
-	},
+		assert.strictEqual(code.indexOf('sourceMappingURL'), -1);
+	}
 };
diff --git a/test/sourcemaps/samples/existing-inline-sourcemaps-combined/_config.js b/test/sourcemaps/samples/existing-inline-sourcemaps-combined/_config.js
index d77fb87c969..09a35337622 100644
--- a/test/sourcemaps/samples/existing-inline-sourcemaps-combined/_config.js
+++ b/test/sourcemaps/samples/existing-inline-sourcemaps-combined/_config.js
@@ -1,8 +1,9 @@
 const assert = require('assert');
 
 module.exports = {
-	description: 'combines existing sourcemap files into one',
+	solo: true,
+	description: 'removes existing inline sourcemaps',
 	async test(code) {
-		assert.doesNotMatch(code, /sourceMappingURL=data:/);
-	},
+		assert.strictEqual(code.indexOf('sourceMappingURL'), -1);
+	}
 };